a. Field of the Invention
The present invention relates to pranoprofen-containing, suspending medicinal compositions, and more specifically to pranoprofen-containing, suspending medicinal compositions, such as syrups, which feature good long-term stability of pranoprofen, remain in a well-dispersed state with good fluidity over a prolonged period of time, and are palatable.
b. Description of the Related Art
Pranoprofen is a non-steroidal anti-inflammatory agent having excellent anti-inflammatory effects and analgesic effects and is considered to have a small incidence rate of side effects. It has therefore found increasing utility, especially in the field of pediatrics. As dosable preparation forms for use in the field of pediatrics, syrups are desired.
With a view toward preparing syrups of pranoprofen, the present inventors have therefore proceeded with a variety of research. As a result, it has been found that pranoprofen exhibits poor stability when prepared into a dissolving syrup and a suspending syrup is hence preferred for pranoprofen from the standpoint of stability.
Suspending medicinal compositions, led by suspending syrups, are however required to contain an effective ingredient evenly in the compositions without settling and further to readily flow out of containers as needed. They are accordingly required to remain in a well-dispersed state with good fluidity over a prolonged period of time.
To fulfill such requirements, the following methods are generally used: (1) to reduce the size of suspended particles, (2) to minimize the difference in density between the suspended particles and a dispersion medium, and (3) to increase the viscosity of the dispersion medium. Although some improvements can be observed according to the method (1) or (2), the method (3) is accompanied by the drawback that higher viscosity naturally leads to poor fluidity thereby making it difficult to dispense the suspending medicinal composition into smaller containers and also to administer the composition. It has therefore been difficult to prepare a pranoprofen-containing suspending medicinal composition which remains in a well-dispersed state with good fluidity over a prolonged period of time.